Limit device for electric elevators.



a. L. DE CAMP. LIMIT DEVICE FOR ELECTRIG ELEVATORS APPLICATION FILED SEPT- 25. 191?- 1,258,393. Patented Mar. 5, 1918.

2 SHEETS-SHEET I;

\Nmwsses:

R. L. DE CAMP.

LIMIT DEVlGE FOR ELECTRIC ELEVATORS.

APPLICATION HLED SEPT. 25. 1911.

1,258,393. Patented Mar. 5, 1918.

2 SHEETS-SHEET 2.

a 1. n .3 0 4yww noY L. De CAMi, or Los memes,

nos ANGELES, onmronn nn" oonrona'rron oroamronnm. r A

To all whom it ma? c mm.- l g I Be it known t at I, Roy L. De CAMP, a citizen of theUnited States, residing at Los Angeles, in the county of LosAngcles and State of California, have invented 'n new and useful 1 Limit Device for Electric Elevators, OfWhlGh the following isa speeds ficationi a r a a a 1 1 This inventionpertains to devices of the character designed to work automatically to break the circuit; operating the elevator when theload on the elevator moves up and down beyond predeterminedlevels and when, for any reason, the cable becomes slack as it wou1d;for instance, if the cable broke.

a device of this character-of maximum snuplicity and thereforeof comparatively shght Another object is to in the subjoinecl detail description;

The accompanying drawingsillustratethe invention: a

Figure 1 is a perspective viewof anelectricallyoperated elevator with the lnventnni.

Fig. 5 is an end elevation ofthe; slack cable device, a fragment ofthecable drum also being shown."

Fig. 6 1s a reduced plan of the slack cable device.

The elevator cable drum 1 is mounted on a drum shaft 2 whlchis ournaled 111 standards 2, 3; sa d shaft being driven through suitable near reduction by an electric motor indicated at 4. This construction iswell knownin the artpertaining to electric elevators and therefore it is unnecessary to illustrate and describe sa d construction in detail.

The drum shaftQ is extended as indicated as. the extension being provided with .screw threads 6 and being connected bya collaror eccentric hub 7 and bolts 8 to the main portion of the drum shaft. @The bolts l Specification of Letters Patent.. M131, 5, jn ncafio mea s temberzais v. 1ssam19sm i i An object of the invention is to produce effect the} foregoing by employing 'a-single switch. 1

Other objects and advantageswill appear end elevation of the invention v "triers: nnvienron nnnermo nnnvn'rons 8 through the hub? into the 1 adj a cent end of the main portion of the drum a shaft and the hub 7Iis keyed at 9 to theshaft extension 5. Journaled onthe .hub 7. is an caLrro'n'mn,iissrenon ro time their wens; or I 5 7 eccentric 10 andjoin'naled ontheeccentric is an eccentric strap 100 which connected by a rod 11 to a elevis 12, therebeing screw-' threads 13 onthe rod andnutslet so that The clevis 12 is pivoted at 15 to an arinlG Which in turn ispivoted at 17 to a switch 18f0r the motor 4, the operating levero t the switch being shown at 19. Between the p the clevis and rodcan be relativelyadjusted.

arm 16 and the switch lever 19 is interposed a coil spring 20. :Thus when the arm 16 is depressed the level-"lilwillbe moved to open the switch. The type of switch shown in the drawings 18 well understood in 1 the art pertaining to electric switches audit is therefore unnecessary to illustrate and dc scribe thesamein 'detailherein. It is suiticient to state regarding operation of the switch 18 that when thelever 1:9 in the raised position as in Fig.- 3 tl'leswitch' parts are in their circuit-closing" positions 1. and

when said lever is in the ilowered position.

the switch parts arein their circuit breaking 130811310118. i

Traveling on the shaft extension dis a A nut 21 which engages the.screwthreads l3 andwhichis shiftably mounted on pins tllfltillllll'llllttVGlilleill' ends fastened in a pin spacer'23 and in theeccentriclO. Thus when the drum shaft lie turned in one direction the nut 21 will travel toward one end, of the; shaft andwhen the drum is 7 turned the opposite directioiti the lillll wllll travel toward the oppositeentfl oiithe shaft.

Adjustably fastened to the shaft extension 5 by bolts 24ers stops 25, 26, the stop 25 i being between the traveling nutqfll and pin spacer 23 and the stop26 beingbetwoeu the travelingnut and eccentric 10. The stops are provided with clutch teeth 27 adapted toengage clutch teeth 28 atthe opposite faces oi. the travelingnut 21 when the travelmg {nut is moved sufficiently far in either direction to. causethe' engagement. It "is Y now clear that when the "drum shaft 2 retates in oncdirecl'ionpr another a suflicieni:

number of "times thetravelingmut 21 will engage one or the other-of the stops 25;26. and that. when the engagement occurs the travelinnut 21 will be rotated, thus rotating tfepms 22 so as to turn the e'ceentric hub 7 which in turn operates the eccen trio 10 to push the connecting rod 11 and its clevls 12 downward so as to throw the switch lever 19 from its circuit closing. position.

shown in Fig. 3 to its circuit brealcing posit1on. p

The clev1s12'1s provided with a slot 29 in which is inserted anarln 30 mounted on a shaft 31. Means operative by slackening ofthe cable 32 are provided toeause turning of the shaft 31 and said means together with the arm 30 and shat't 31 constitute a slack cable de ice. These means may he variously constructed andseveral different types are well known in the art pertaining to electric elevators andztomake the operationot the invention clear one such device willbedes scribed and 1s constructed as follows; The

shaft 31 is providedwith an arm ou pivoted v at 34 to a rod 35 whichgin turn is pivoted v lows at 36 to a sleeve 37; shittable on one u of a pair of levers 38. The levers 38 are pivoted at one end at 39 to bearingslO and the other ends of the levers 38 journal a sheave shaft 41 having mounted thereon a sheave a-z-cver which the cable 32 runs as clearly shown in Fig.5. 1 i c The shaft 31 is provided. with an arm 43 having thereon a counterbalance 4a tend mg to turn the shaft; 131 in a directionto more the free end of; the arm- .30 clownward in the slot 29 to engage the lower end of-the slotandthereby move the clevis downward to cause breaking of theeleetric circuit the same as previously described; 1 \Vh'en the cable 32 is taut it. holds the sheave 42 toward the drnmagainst the tendency. oi the counterbalance ttfito move the sheave away from the drum. I

It is understood thatthe switch 18 is connected in the electric circuit cont-rollingthe motor 4: so that when the switch lever 19 is in the position shown in Fig. 3 the motor.

will operate to turn'the drum and when the lever 19 is moved downward theelectric current supplied. to the motor will be cut off so that the drum 1 will come to a stop.

Theoperation of the invention is "as fol- It for anyreason thecable 32 becomes slack, when the elevator is inoperation, the counterbalance 14: will turn the shaft 31 in a direction to move the arm 30as indicated by the arrow (1, Fig. 5, so-thatthe outer end of said arm will engage the lower end of the clevis slot 29 to movethe switch lever 19 into circuit-breaking position.

Assuming that the motor aism operation to turn the drum in the direction "of the" arrow. 6, Figs. 1' and 5, to wind up the cable 32, it is clear that if the motor is not thrown out of operation by the operator before the traveling nut 21 engages the stop 25, the engagement of the nut with said step will cause turning of the nut 21, thus causing operation of the eccentric 10 ashereinbe't'o're noted: to move. the switch lever 19 into circuit-breaking ipo'sitioni Assuming that thedrum l is being turned by the motor 4 in a direction opposite to that indicated. by the arrow b to unwind the cable 32, it i clear that the nut 21 will b ecaus'ed to travel toward the stop 26and that, if the motor is not thrown out o-fcomlnission by the operator before the nut .reachesthe stop, en gagement of the nut and stop will. cause 'the nut 21 to be rotated thus causing rotation of the eccentric as before, butinthe opposite direction, so as to cause throwing of the switch arm 19 into circuit-breaking position.

The slot 29 permits motion. of the rodll with respect to the arm-3O so that thelimit device can operate irrespective of-the slack cable device. Thus it is seen thatmeans are provided wherebyrotation of thedrum a predetermined number of times in. either direction will throw the switch withoutaffecting the slack cable device which likewise is ca-' pable of th'rowingthe same switch.

From the foregoing it is clear that the. invention employsbut one switch for opening the elevator operating circuit inv event of the cable beconiingslack andalso in eventof the operator not throwing the motor out ofcpmmission bei'o'rethe load on theelevato1- has reached either one on two predetermined positions due to" operation of'fthe cable 32,

one pOSitlOnbQing due to winding ot' the unwinding of the cable.

Iclaima y 1. The combination with a .drumhaving a. cable thereon anda motorto turn the drum, of a switch for the motor, an eccentric operatively connected with-the switch, means operative by "turning of the drum to move the eccentric, and; aslack; cable deviceoperatively connected with the connections betweenthe switch and eccentric.

2. Thecombination with a drum having. a cable thereon and a motor to turn the drum, of a switch for themotor, ashaft for the drum having an extension provided with screw-threads, a nut to travel alongrsaid screw-threads, aneccentric operatively con nected withthe s'vvitchand rotative by turn ing of the nut, means rota-tive by the shaft extension adapted to clutch the nut when the nut travels a predetermined distance in either direction, and a slack cable-device opthe eccentric and switch.

3. The combination with adrum having a cable tliiereon and a notoi to turnthe drum, of a switch for the motor providedwvith an arm, a limit device operative byturning of the drum a predetermined number et'times in one direction, a shaft, means connecting eratively connected with the connectionsol the limit device and shaft to the switch arm,

and means operative by slackening of the cable to cause turning of the shaft. 7

4L. The combination with a drum havlng a cable thereon] nnda motor to till-11 the drum, of a switch for the'motor, means 0pelatlve by turning of the dl'um a predetermined number oftimes in either direction to throw the switch, said means ncluding a slotted member, anda slack cable (iOVlCG indrum, of a switch for. the motor havingan operating member, a rodconnected wlth the operating member, means operative by turn mg of the c'hi'i'un to move the roch'and means Copier 011111: patent may be obtained for five cents each, by addressing the Commissioner of Patents,

loosely v'eoinieeted Withthe rod and opei'aa tive by slackening of the cable to move said rod. I a

6. The Combination with a drum having a cablefthei'eon and a motor to turn the drum, of a switch for the motor havin an-operat ing member n-i'od oonneeted Wit 1 the opetatthe drum in either -ciii'oction to move the 170d,.anci means loosely connected Wlth the rod anctope1'ati\"e by slackening of the cable no to move said Ted. r I Signed at Los Angeles, Oahfornia,

this 7 day of Sept; 1917. a v

i ROY L. DE, CAMP.

Witnesses:

f N. S. Hoae,

FRANK WVESTALL.

ing member, means operative by turning of 

